Mesoscale Discussion 1503

Issued

Jul 4, 2011, 6:09 PM CDT (23:09 UTC)

Expired

Jul 4, 2011, 8:15 PM CDT

In force

2 hr

Issued by

the Storm Prediction Center

The Duluth radar (KDLH), 169 km from the middle of the area, began a volume at 23:11 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

• Severe Thunderstorm Watch 598Jul 4, 7:15 PM CDT

690 
ACUS11 KWNS 042309
SWOMCD
SPC MCD 042309 
MNZ000-NDZ000-050115-

MESOSCALE DISCUSSION 1503
NWS STORM PREDICTION CENTER NORMAN OK
0609 PM CDT MON JUL 04 2011

AREAS AFFECTED...PORTIONS ERN THROUGH S-CENTRAL ND...NRN MN
INCLUDING ARROWHEAD AND LS NORTH SHORE.

CONCERNING...SEVERE THUNDERSTORM WATCH 596...

VALID 042309Z - 050115Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 596
CONTINUES.

SVR TSTMS OVER NWRN MN MAY GROW UPSCALE INTO FORWARD-PROPAGATION MCS
AND MOVE SEWD ACROSS REMAINDER NWRN/N-CENTRAL MN...WITH SOME
BACKBUILDING STILL POSSIBLE INTO ERN ND.  ADDITIONALLY...MORE
DISCRETE/WIDELY SCATTERED DEVELOPMENT OVER ERN ARROWHEAD AND
ADJACENT PORTIONS ONT SHOULD MOVE SEWD WITH AT LEAST EPISODIC
SUPERCELLULAR MODES POSSIBLE...AND ATTENDANT RISK OF LARGE HAIL AND
SVR GUSTS.  ADDITIONAL WW MAY BE REQUIRED FOR NRN MN E OF WW 596. 
EXISTING WW MAY BE CLEARED BEHIND COLD FRONT. 

2230Z SFC MESOANALYSIS SHOWS COLD FRONT FROM SRN MB SWWD ACROSS
NERN/S-CENTRAL ND...MOVING SEWD THROUGH DVL/BIS AREAS...AND FCST TO
CONTINUE SEWD ACROSS REMAINDER ERN/SRN ND AND INTO NWRN MN THROUGH
WW DURATION.  PREFRONTAL CONFLUENCE LINE...DRIFTING EWD...IS
ANALYZED FROM RICHLAND COUNTY ND NNEWD OVER FAR...CKN AND MARSHALL
COUNTY MN.  QUASISTATIONARY/MESOSCALE BAROCLINIC ZONE IS DRAWN FROM
COOK COUNTY MN NWWD NEAR ONT STATIONS CWCH AND CYHD.  CAPPING SO FAR
HAS HINDERED MAINTENANCE OF CONVECTIVE TOWERS ALONG COLD FRONT AND
CONFLUENCE LINE.  THOUGH INITIATION CANNOT BE RULED OUT ALONG EITHER
OF THOSE BOUNDARIES BEFORE OUTFLOW FROM MCS OVERTAKES THEM...THOSE
INTERSECTIONS MAY SERVE AS LOCALIZED FOCI FOR ENHANCED LIFT DURING
NEXT 2-3 HOURS.  PRIMARY CONCERN ATTM FOR ORGANIZED SVR THREAT IS
POTENTIAL FOR EXPANSIVE COLD POOL WITH STG LEADING-EDGE ASCENT
DEVELOPING FROM ACTIVITY NOW OVER NWRN MN...LEADING TO QLCS WITH
WIND DAMAGE THREAT SPREADING SEWD OVER NRN MN.  MORE BACKED SFC
WINDS E OF CONFLUENCE LINE WILL LEAD TO STRONGER STORM-RELATIVE
INFLOW VERSUS FARTHER W.  PROSPECTIVE INFLOW-LAYER AIR MASS WILL BE
FAVORABLE WITH SFC DEW POINTS 70S F CONTRIBUTING TO CORRIDOR OF
MLCAPE 3000-4500 J/KG FROM JMS/ABR AREAS NEWD ACROSS NWRN MN.  CINH
WILL INCREASE WITH SEWD EXTENT OVER NRN/CENTRAL MN GIVEN LOWER
BOUNDARY LAYER THETAE...HOWEVER BY THAT TIME FORCED ASCENT MAY BE
SUFFICIENT TO MAINTAIN MCS INTO THOSE AREAS.  SMALL-SCALE
CONCENTRATION OF VORTICITY/LOW-LEVEL SHEAR ALONG ARROWHEAD/ONT
BOUNDARY ALSO MAY SUPPORT SUPERCELL STRUCTURES...WITH WEAKLY CAPPED
AIR MASS TO ITS SW...MLCAPE 1500-2000 J/KG AND EFFECTIVE SHEAR
MAGNITUDES 35-45 KT.

..EDWARDS.. 07/04/2011

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...DLH...MPX...FGF...BIS...

LAT...LON   47040028 48979736 48979508 49379510 49369495 49299479
            49089477 48959467 48769471 48699423 48659424 48609382
            48529380 48539348 48639342 48599286 48519262 48439276
            48449247 48199237 48359224 48379206 48219196 48169168
            48089165 48059137 48249084 48079076 48119009 47998991
            48038977 48008957 48068939 47908974 47649071 46779210
            46409364 46039616 45999929 47040028

Mesoscale Discussions in Minnesota, 2011Mesoscale Discussions in North Dakota, 2011Every mesoscale discussion in 2011

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.